RESUMEN
We report on a child with ptosis, epicanthal folds, depressed nasal bridge, carp-shaped mouth, low set ears, hirsutism, pectus excavatum, and developmental and language delay presenting with a balanced complex chromosomal rearrangement (CCR). R- and G-banding methods and fluorescence in situ hybridization were used to document that this is a complex translocation with five breakpoints involving chromosomes 1, 7, 10 and 21.
Asunto(s)
Anomalías Múltiples/genética , Translocación Genética/genética , Técnicas de Cultivo de Célula , Bandeo Cromosómico , Cromosomas Humanos Par 1/genética , Cromosomas Humanos Par 10/genética , Cromosomas Humanos Par 21/genética , Cromosomas Humanos Par 7/genética , Femenino , Humanos , Hibridación Fluorescente in Situ , Lactante , LinfocitosRESUMEN
Complex chromosomal rearrangements are very rare events in the human population. According to our knowledge on the consequences of simple reciprocal translocations for male fertility, translocations involving three or more chromosomes are thought to lead to severe reproductive impairments in terms of meiotic disturbance or chromosomal imbalance of gametes. We report the case of a 48 year old man whose sperm count revealed either oligozoospermia (<10(3) spermatozoa/ml) or azoospermia. He was referred to the laboratory for in-vitro fertilization after intracytoplasmic sperm injection. Cytogenetic investigations showed a complex chromosomal rearrangement involving firstly a translocation between the short arm of chromosome 7 and the long arm of chromosome 13 and secondly a translocation between the short arm of the same chromosome 13 and the short arm of chromosome 9. Diagnosis was ascertained by fluorescence in-situ hybridization and staining of the nucleolar organizer regions. Theoretical study of the translocated chromosomes predicted a 'chain' configuration of the hexavalent at the pachytene stage of meiosis. In all, 32 modes of segregation were considered and only one resulted either in a normal or a balanced gamete karyotype. Genetic counselling and choice of appropriate artificial reproduction technique are discussed.